1. Field of the Invention
The invention relates to character animation, and specifically to muscle deformation of an animated character.
2. Description of Background Art
Computer-generated graphics have achieved the ability to create astonishingly photorealistic stationary characters. However, when these characters are animated, their realism typically suffers. It is common for viewers to complain that computer-animated characters sometimes move rigidly, unnaturally, and without convincing liveliness.
One important aspect of the animation of lifelike characters is realistic muscle deformation. After all, most characters are more than just bones and joints, and ignoring the deformation of muscles tends to produce motion that is lifeless and plastic.
One approach to muscle deformation is to define a muscle or muscle-deformed skin mesh (muscle-based mesh) for various sample poses of a character. The muscle-based mesh for other poses can be interpolated from the muscles meshes of the sample poses. However, this approach has serious limitations in its ability to produce lifelike characters. Since the sample poses are usually made up of only joint angles, the interpolated muscle deformations cannot react to changes in pose transition speed or external loads acting on the character. Muscles deform, but the deformation is not responsive to the same physical forces as those acting on a real character.
Existing techniques for muscle deformation fail to adequately account for external loads, gravity, acceleration, and non-zero character velocity. Therefore, what is needed is a system and method for muscle deformation capable of reflecting external loads, gravity, acceleration, and non-zero character velocity.